PROJECT SUMMARY Asthma and chronic obstructive pulmonary disease (COPD) are common chronic lung diseases that are diagnosed in more than 30 million adults in the United States. However, diagnostic error (DE), considered one of the most common and harmful of patient-safety problems by the Institute of Medicine, occur frequently with asthma and/or COPD and disproportionately affect minorities and the underserved. DE leads to lost opportunities to identify other chronic conditions, avoidable morbidity and mortality, unnecessary costs to patients and health systems, and poor quality of care. Spirometry is a simple, mobile, and essential test that is necessary for the diagnosis of COPD, but studies show that only about a third of patients have spirometry testing and an estimated 30-50% of patients with an existing diagnosis of asthma and/or COPD experience diagnostic error. Prior interventions to improve spirometry use have had limited effects. A new paradigm to improve guideline based care for asthma and COPD which includes spirometry is needed and can lead to a better understanding of DE and improved patient safety and patient-centered outcomes. The REDEFINE study (Reducing Diagnostic Error to Improve PatieNt SafEty in COPD and Asthma) is a comparative effectiveness trial that will incorporate community health workers working collaboratively with primary care physicians to address identified barriers to guideline based care which includes spirometry for the diagnosis of asthma and COPD for patients at risk for DE. The REDEFINE study will enroll 60 primary care physicians and 400 adults who are 40 years of age or older, have a diagnosis of asthma and/or COPD but have not had spirometry testing. Participants in the intervention group will receive the REDEFINE program which includes spirometry testing near the time of their primary care visit in addition to guideline based education and will be compared to participants who receive usual care. The REDEFINE study will answer the following questions: ? What is the prevalence of and characteristics associated with DE in asthma and/or COPD in an underserved population? ? What is the effectiveness of the REDEFINE program compared to usual care on health care utilization and patient-centered outcomes (including respiratory medication use, all-cause emergency room visits, and all-cause hospitlizations)? ? What is the cost impact and cost effectiveness of the REDEFINE program versus usual care? THE REDEFINE study is an innovative approach that aims to reduce DE and improve patient safety for patients with a diagnosis of COPD and asthma in an underserved primary care ambulatory setting. The approach includes guideline based recommendations including spirometry within the pragmatic framework of a busy primary care practice, addresses limitations in past efforts and newly identified barriers to reduce DE in asthma and COPD in an underserved population with multiple chronic medical conditions.